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Free download in PDF Op Amp Multiple Choice Questions & Answers for competitive exams. These objective type questions are very important for competitive exams like IIT-JEE, GATE, CAT etc. These short solved questions or quizzes are provided by Gkseries.
(1)
A differential amplifier ……………..
[A]
is a part of an Op-amp
[B]
has one input and one output
[C]
has two outputs
[D]
answers (1) and (2)
Answer: answers (1) and (2)
(2)
When a differential amplifier is operated single-ended, …………
[A]
the output is grounded
[B]
one input is grounded and signal is applied to the other
[C]
both inputs are connected together
[D]
the output is not inverted
Answer: one input is grounded and signal is applied to the other
(3)
The common-mode gain is ………..
[A]
very high
[B]
very low
[C]
always unity
[D]
unpredictable
(4)
If ADM = 3500 and ACM = 0.35, the CMRR is ……….
[A]
1225
[B]
10,000
[C]
80 dB
[D]
answers (1) and (3)
Answer: answers (1) and (3)
(5)
Of the values listed, the most realistic value for open-loop voltage gain of an OP-amp is ……
[A]
1
[B]
2000
[C]
80 dB
[D]
100,000
(6)
The output of a particular Op-amp increases 8V in 12μs. The slew rate is …….
[A]
90 V/μs
[B]
0.67 V/μs
[C]
1.5 V/μs
[D]
none of these
(7)
For an Op-amp with negative feedback, the output is …….
[A]
equal to the input
[B]
increased
[C]
fed back to the inverting input
[D]
fed back to the noninverting input
Answer: fed back to the inverting input
(8)
Negative feedback ………..
[A]
increases the input and output impedances
[B]
increases the input impedance and bandwidth
[C]
decreases the output impedance and bandwidth
[D]
does not affect impedance or bandwidth
Answer: increases the input impedance and bandwidth
(9)
If the feedback resistor in Q15 (above question) is open, the voltage gain …….
[A]
increases
[B]
decreases
[C]
is not affected
[D]
depends on Ri
(10)
A voltage follower ……….
[A]
has a voltage gain of 1
[B]
is noninverting
[C]
has no feedback resistor
[D]
has all of these
(11)
The input offset current equals the ……….
[A]
difference between two base currents
[B]
average of two base currents
[C]
collector current divided by current gain
[D]
none of these
Answer: difference between two base currents
(12)
The node voltage at the top of the til resistor is closes to ……….
[A]
collector supply voltage
[B]
zero
[C]
emitter supply voltage
[D]
tail current times base resistance
(13)
The tail current in a differential amplifier equals …….
[A]
difference between two emitter currents
[B]
sum of two emitter currents
[C]
collector current divided by current gain
[D]
collector voltage divided by collector resistance
Answer: sum of two emitter currents
(14)
The input impedance of a differential amplifier equals r’e times ……
[A]
β
[B]
RE
[C]
RC
[D]
2β
(15)
The common-mode voltage gain is ………
[A]
smaller than differentail voltage gain
[B]
equal to differential voltage gain
[C]
greater than differential voltage gain
[D]
none of the above
Answer: smaller than differentail voltage gain
(16)
The input stage of an Op-amp is usually a ……….
[A]
differential amplifier
[B]
class B push-pull amplifier
[C]
CE amplifier
[D]
swamped amplifier
Answer: differential amplifier
(17)
Current cannot flow to ground through …….
[A]
a mechanical ground
[B]
an a.c. ground
[C]
a virtual ground
[D]
an ordinary ground
(18)
A non inverting closed loop op amp circuit generally has a gain factor
[A]
Less than one
[B]
Greater than one
[C]
Of zero
[D]
Equal to one
(19)
An ideal OP-AMP is an ideal
[A]
Current controlled Current source
[B]
Current controlled voltage source
[C]
Voltage controlled voltage source
[D]
voltage controlled current source
Answer: Voltage controlled voltage source
(20)
The ideal OP-AMP has the following characteristics.
[A]
Ri=∞ ,A=∞ ,R0=0
[B]
Ri=0 ,A=∞ ,R0=0
[C]
Ri=∞ ,A=∞ ,R0=∞
[D]
Ri=0 ,A=∞ ,R0=∞
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